<?php
//dezend by http://www.yunlu99.com/ QQ:270656184
defined('BASEPATH') || exit('No direct script access allowed');
class CI_DB_mssql_forge extends CI_DB_forge
{
	/**
	 * CREATE TABLE IF statement
	 *
	 * @var	string
	 */
	protected $_create_table_if = "IF NOT EXISTS (SELECT * FROM sysobjects WHERE ID = object_id(N'%s') AND OBJECTPROPERTY(id, N'IsUserTable') = 1)\nCREATE TABLE";
	/**
	 * DROP TABLE IF statement
	 *
	 * @var	string
	 */
	protected $_drop_table_if = "IF EXISTS (SELECT * FROM sysobjects WHERE ID = object_id(N'%s') AND OBJECTPROPERTY(id, N'IsUserTable') = 1)\nDROP TABLE";
	/**
	 * UNSIGNED support
	 *
	 * @var	array
	 */
	protected $_unsigned = array('TINYINT' => 'SMALLINT', 'SMALLINT' => 'INT', 'INT' => 'BIGINT', 'REAL' => 'FLOAT');

	protected function _alter_table($alter_type, $table, $field)
	{
		if (in_array($alter_type, array('ADD', 'DROP'), true)) {
			return parent::_alter_table($alter_type, $table, $field);
		}

		$sql = 'ALTER TABLE ' . $this->db->escape_identifiers($table) . ' ALTER COLUMN ';
		$sqls = array();
		$i = 0;

		for ($c = count($field); $i < $c; $i++) {
			$sqls[] = $sql . $this->_process_column($field[$i]);
		}

		return $sqls;
	}

	protected function _attr_type(&$attributes)
	{
		if (isset($attributes['CONSTRAINT']) && (strpos($attributes['TYPE'], 'INT') !== false)) {
			unset($attributes['CONSTRAINT']);
		}

		switch (strtoupper($attributes['TYPE'])) {
		case 'MEDIUMINT':
			$attributes['TYPE'] = 'INTEGER';
			$attributes['UNSIGNED'] = false;
			return NULL;
		case 'INTEGER':
			$attributes['TYPE'] = 'INT';
			return NULL;
		default:
			return NULL;
		}
	}

	protected function _attr_auto_increment(&$attributes, &$field)
	{
		if (!empty($attributes['AUTO_INCREMENT']) && ($attributes['AUTO_INCREMENT'] === true) && (stripos($field['type'], 'int') !== false)) {
			$field['auto_increment'] = ' IDENTITY(1,1)';
		}
	}
}

?>
